A technique has been known, in which a power conversion device includes an inverter that receives power from a direct-current power supply system and drives a motor as a load, a fin as a cooling unit that cools down the inverter, a first core including a through hole that allows passage of a high voltage line that connects the direct-current power supply system and the inverter and a ground line that grounds the inverter, a first ground line that grounds the fin, a second ground line that grounds the motor, and a second core including a through hole. In this power conversion device, the first ground line is connected to a ground line on the side of the direct-current power supply system with respect to the first core, and a resonance path that circulates the inverter, the fin, the first ground line, a common ground point of the first ground line and the second ground line, the motor, the second ground line, and the inverter is arranged to pass through the through hole of the second core, thereby increasing high frequency impedance of the resonance path and suppressing a noise source current in the power conversion device (see, for example, Patent Literature 1).